In the course of conducting activities involving multiple parties, a need often arises for people to meet to share information, exchange data or documents, discuss topics of mutual interest, or collaborate in preparing various documents or other work product. It may not be desirable, or possible, for all of the participants in a meeting to be in the same physical location at the same time, in which case meeting objectives may be achieved using various communication equipment and networks as tools for facilitating remote collaboration in a multimedia collaboration session. It can be useful for such a session to include a variety of media types that include the participants' voices, video images, shared documents, text messages, drawings, computer screen images, etc.
Several systems exist for configuring various devices and networks into collaboration sessions. For example, multimedia collaboration systems require many components and resources such as server equipment, networking equipment, and media processing and distribution. Session participants may be distributed in a wide variety of locations, e.g., in the same building, multiple buildings, across a city, across a country, or internationally. Thus, the communication links between participants vary greatly in quality, bandwidth, and usage cost.
Conventional multimedia collaboration architectures can be divided into two basic architectures: central-server and peer-connected. In a central-server architecture, all participant clients communicate with a single server that performs control, routing, and media processing functions. The server is located at a point in the network topology that is often not optimal for a given session's participants. In addition, a central server architecture provides all media services from a single point in the network, preventing separation of media services and further preventing location of specific media services at optimal points in the network. Accordingly, it is often not possible to provide the best combination of cost, performance, and bandwidth usage for a session's participants.
In a peer-connected architecture, participant clients communicate directly with one another. This architecture makes central control and coordination difficult, and also limits the size and media capability of the conference, there being no way to perform tasks requiring aggregate media processing, such as audio mixing or video switching between speakers.
Conventional collaboration systems also often require participants in sessions using certain media types, such as video, to install expensive equipment, use specialized conference rooms, or maintain high-performance network connections. Moreover, collaboration systems in use today often limit the performance experienced by all participants to that provided by the slowest network connection. Other existing systems offer a degree of flexibility in location of components, but are limited to a single media type. The telephone system is an example of such a system.